• Environmental Engineering Research
• /
• v.22 no.3
• /
• pp.312-319
• /
• 2017

The treatment of dyeing wastewater is not easy because dyes are mainly aromatic, heterocyclic compounds. The most effective technologies and methods to treat dyeing wastewater are costly and involve materials that are difficult to regenerate after use. Therefore, it is necessary to develop cost-effective, eco-friendly technologies to treat dyeing wastewater. The aim of this study was to investigate the removal of sulfur blue 11 (CI 53235) anionic dye using methyl esterified sericite (ME-sericite) adsorbents in an aqueous solution. The results are discussed in terms of the ME-sericite particle size, temperature, pH value and initial sorption rate according to the initial sulfur blue concentration. In addition, we analyzed the adsorption kinetics using a Pseudo-second-order model with the desorption and reusability. The methyl esterification caused a considerable increase in the specific surface area from 4.45 to $17.62m^2/g$. The ME-sericite adsorbents successfully removed > 98% of the sulfur dye in the aqueous solution. For the adsorption of 1 mg of sulfur dye, approximately 4.6 to 6.6 g/L ME-sericite were required. The desorption process was carried out by mixing a NaOH eluent to desorb 90.56% of the sulfur dye with 2 h of contact time. Thus, the ME-sericite is a promising adsorbent to treat dyeing wastewater due to its low dose requirement, high removal efficiency and inexpensive material.

• Particle and aerosol research
• /
• v.18 no.3
• /
• pp.69-77
• /
• 2022

In order to understand the characteristics of fine particles emitted from coal-fired power plant stacks, it is important to analyze the size distribution and components of particles. In this study, particle size distributions were measured using the ejector-porous tube dilution device and an ELPI system at a stack in a coal-fired power plant. Main elemental components of particles in each size interval were also identified through TEM-EDS analysis for the particles collected in each ELPI stage. Particle size distributions based on number and mass were analyzed with component distributions from 0.006 to 10 ㎛. The highest number concentration was about 0.01 ㎛. The main component of the particles consisted of sulfur, which indicated that sulfate aerosols were generated by gas-to-particle conversion of SO2. In a mass size distribution, a mono-modal distribution with a mode diameter of about 2 ㎛ was shown. For the components of PM1.0 (particles less than 1 ㎛), the abundance order was F > Mg > S > Ca, and however, for the components of PM10 (particles less than 10 ㎛), it was in the order of Fe > S > Ca > Mg. The elemental components by particle size were confirmed.

• Journal of the Korean Society of Safety
• /
• v.1 no.1
• /
• pp.27-32
• /
• 1986

To remove sulfur dioxide from flue gas by the method of metal oxide, copper powder of average diameter $2.4\mu\textrm{m}$and $51\mu\textrm{m}$ were used in a fixed bed reactor over a, temperature range of $300^{\circ}C-500^{\circ}C$. Copper oxide reacts with sulfur dioxide producing cupric sulfate and it can be regenerated from the latter by using hydrogen or methane. Experimental results showed that the reaction rate was increased by the increase of reaction temperature in the range of $300^{\circ}C-422^{\circ}C$ and the removal efficiency of sulfur dioxide was high in case of small size copper particle. However the removal efficiency was decreased at higher temperature due to decomposition of cupric sulfate. The rate controlling step of this reaction was chemical reaction and deactivating catalysts model can be applied to this reaction. The rate constants for this reaction and deactivation are as follows ： k＝8,367exp(-10,298/RT) Kd＝2.23exp(-8,485/RT)

• Journal of Korean Society for Atmospheric Environment
• /
• v.20 no.2
• /
• pp.225-236
• /
• 2004

Diesel engines which emit a lot of PM and NOx have been known as a main air polluter. Especially, diesel particulate matters (OPM) including black smoke are hazardous air pollutants to human health and environment. The nations retaining advanced engine technologies have reinforced emission regulations. To meet these regulations diesel engine manufacturers have developed low-emission diesel engines, aftertreatment equipments, alternative fuel technologies and so on. In this study, particle number concentrations characteristics according to particle size and engine driving conditions were analyzed when these low-emission technologies were applied. There was a tendency of increasing particle number concentrations from heavy-duty diesel engines with increasing engine rpm and load rate. In the cases of COPF (Catalytic Diesel Particulate Filter), CNG (Compressed Natural Gas) engine and ULSD (Ultra Low Sulfur Diesel) more than 99% of particle number concentration were removed.

• Clean Technology
• /
• v.8 no.1
• /
• pp.11-17
• /
• 2002

Petcokes is the final product obtained from a refinery process. This petcokes includes high percentage of inorganic and sulfur compounds. Currently, the petcokes produced from domestic refinery plants include more than 6% of sulfur. To use petcokes as valuable raw materials, the weight percentage of sulfur must be lower than 2% of sulfur. Solvent extraction, thermal desulfurization, and hydro-desulfurization have been used to remove the sulfur. In this study, we attempted new approach to remove the sulfur introducing microwave energy. Microwave increase the reaction rates by providing the fast heating and disconnecting the bonding structure of the molecules. The experiments of microwave thermal desulfurization and microwave plus hydrogen gas were carried out to remove the sulfur. We obtained 68.3% of sulfur removal rate with the 2 hours of reaction time and 1835 W of microwave powder. In the experiment of microwave with hydrogen gas, we obtained 86.4% of sulfur removal rate with the 1.5 hours of reaction time and 1835 W of microwave power. If we increase reaction time or decrease the particle size of petcokes, we expect more than 90% of sulfur removal.

• Clean Technology
• /
• v.8 no.1
• /
• pp.1-9
• /
• 2002

Mild pyrolysis of four different coals (two bituminous coals and two Korean antracite) was investigated. Desulfurization characteristics, weight loss and variation of heating values were studied. As operating variables of experiment, pyrolysis temperature($350{\sim}550^{\circ}C$), pyrolysis time(5~20 min.) and particle size(0~3.55mm) were examined. The maximum sulfur removal rate of bituminous coal and anthracite were 38% and 28%, respectively. The optimum mild pyrolysis conditions were 10~15 min for pyrolysis time and $450{\sim}550^{\circ}C$ for pyrolysis temperature. The mild pyrolysis was effective to reduce organic sulfur content. Heating values of char per mass after pyrolysis increased about 5% compared to raw coal. The effect of coal particle size on the desulfurization was not observed.

• The Korean Journal of Nuclear Medicine
• /
• v.32 no.3
• /
• pp.298-304
• /
• 1998

Purpose: We evaluated the usefulness of Re-188 sulfur colloid for radiation synovectomy and therapy of intraperitoneal metastasis. Materials and Methods: We investigated the labeling efficiency of Re-188 sulfur colloid on various conditions. The stability of Re-188 sulfur colloid was observed at room temperature for 24 h and in human serum and synovial fluid for 72 h. The particle size distribution of Re-188 sulfur colloid was measured by filtering with various pore size filters. Animal experiment was performed in mice and rabbits. Results: The labeling efficiency of Re-188 sulfur colloid was $64.5{\pm}5.8%$ (n=5) at the conditions of sodium thiosulfate 40 mg, EDTA $Na_2.2H_2O$ 0.8 mg, $KReO_4$ 0.8 mg at pH 1. After purification, the radiochemical purity was higher than 99%. The stability of Re-188 sulfur colloid was high (>99%) at room temperature for 24 h and in human serum and synovial fluid for 72 h. The particle size distribution of Re-188 sulfur colloid was 0.3% ($<1{\mu}m$), 11.2% ($1{\sim}5{\mu}m$), 25.8% ($5{\sim}10{\mu}m$) and 52.8% ($>10{\mu}m$). In mice, 1 h postinjection of Re-188 sulfur colloid into tail vein, uptakes in lung, liver and muscle were $37.30{\pm}5.36$, $32.33{\pm}1.79$, $6.60{\pm}0.02%$ ID/organ respectively. After i.p. injection in mice, the uptakes of extraperitonial organs of Re-188 sulfur colloid at 1 and 24 h were $0.1{\pm}0.1$, $0.4{\pm}0.1%$ ID/organ, and the excretions through urine and feces (${\sim}70 h$) were low ($2.68{\pm}0.80$, $0.95{\pm}0.17%$). When Re-188 sulfur colloid was injected to synovial space of rabbit, the uptake in other organs except knee was very low. Conclusion: Re-188 sulfur colloid showed high labeling efficiency, stability and potency for clinical use.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.17 no.3
• /
• pp.81-89
• /
• 2009

In this experimental study, the effects of clean alternative fuels compatible with diesel combustion on nano-sized particle emission characteristics were investigated in a 0.5L auto-ignited single-cylinder engine with a compression ratio of 15. Because the number concentration of nano-sized particles emitted by automotive engine, that are suspected of being hazardous to human health and environment, might increase with engine fuel considerably and recently attracted attention. So a ultra-low sulfur diesel(ULSD), BD100(100% bio-diesel) and Di-Methyl Ether(DME) fuels used for this study. And, as a particle measuring instrument, a fast-response particle spectrometer (DMS 500) with heated sample line was used for continuous measurement of the particle size and number distribution in the size range of 5 to 1000nm (aerodynamic diameter). As this research results, we found that this measurements involving the large proportion of particles under size order of 300nm and number concentration of $4{\times}10^9$ allowed a single or bi-modal distribution to be found at different engine load conditions. Also the influence of oxygen content in fuel and the catalyst could be a dominant factor in controlling the nano-sized particle emissions in auto-ignited engine.

• Clean Technology
• /
• v.16 no.4
• /
• pp.254-257
• /
• 2010

[ $Mg(OH)_2$ ]slurry was prepared by using natural mineral brucite exploited from Liaoning province in China, and its de-SOx efficiency was examined. The effect of difference in particle size distribution of brucite and activation by hydrothermal treatment were investigated. The de-$SO_2$ efficiency of a finely-milled brucite sample below 1000 mesh with narrow particle size distribution was higher than that of the sample below 80 mesh. On the other hand, the de-$SO_2$ efficiency of brucite sample below 80 meshes was significantly improved by the hydrothermal treatment at 363 K tor 3 h.

• Microbiology and Biotechnology Letters
• /
• v.31 no.4
• /
• pp.400-407
• /
• 2003

In microbial coal desulfurization process (MCDP) by using Acidithiobacillus ferrooxidans, the effect of process variables on pyritic sulfur removal efficiency has been investigated. The inhibitory effect of toxic materials contained in coal matrix on the activity of desulfurizing bacteria have been evaluated in coal extracts, and the results showed that the method was useful to evaluate the applicability of a coal which is to be desulfurization to MCDP. The removal efficiency increased with decreasing particle size and decreases with increasing pulp density, but has no significant influence of particle size and pup densities at high pulp densities over 20 wt%. The mass transfers of gaseous nutrients such as oxygen and carbon dioxide into coal slurry with various pulp densities and coal particle size has been studied in an airlift bioreactor. Mass transfer coefficient was independent of pulp density in coal slurry with fine particle below 175 $\mu\textrm{m}$, but significantly decreased with increasing pulp density over 225 $\mu\textrm{m}$. The coal particles over 575 $\mu\textrm{m}$ were significantly settled to the bottom of bioreactor resulting in poor mixing. Considering mass transfer, pulp density and coal mixing, an optimal size of coal particle for the microbial coal desulfurization process seems to be about 500 $\mu\textrm{m}$.